In this paper, we describe a system that provides a "work-at-home" environment based on a virtual shared room built on a 3D graphics workstation. We realize "Awareness Space" on the system to avoid a tradeoff between providing facility of informal communication and keeping one's workspace from others' awareness information. Also, this system provides the feeling of the presence at virtual office by using "Around View" and "Sound Effect".

In this paper, we propose the virtual office environment which integrates the natural communication and the secure private space. The features of this system are described below. 1) This system has virtual shared room which is based on the idea of "Shared Room Metaphor". 3D graphics on SGI workstation is used for this system. It uses Ethernet (TCP/IP) for signal connection and FDDI (UDP/IP) for continuous media (i.e., realtime audio/video streams). 2) This system realizes the field of view of human being to support natural communication between members by using our "Around View" technique. 3) "Sound Effect" are also used to help users feel the presence of other members. For instance, members hear the opening-sound of the door when someone logs in our system and the sound of footsteps when someone is walking around our virtual room. 4) Sometimes this system avoids unlimited flow of awareness. A person concentrating his/her work may not want to perceive excessive awareness of others. To support such situation, we define "Awareness Space" which restricts the field where other member's awareness is transmitted. Awareness Space changes in size with the degree of concentration which is measured through two factors; the movement of a chair and the frequency of keyboard typing. 5) "Headphone Metaphor"; a picture of headphone is attached above his/her image and changed its color depending on the degree of concentration. The view of this headphone enables other members to recognize his/her state and it can be a criterion he is available to communicate or not.